Field of the Invention
The present invention relates to an optoelectronic device substrate and an optoelectronic device including the same, and more particularly, to an optoelectronic device substrate which can ensure that constituent thin films of an optoelectronic device be flat and that a functional thin film formed to improve the characteristics of the optoelectronic device be structurally stable so that the functional thin film maintains its function and an optoelectronic device including the same.
Description of Related Art
Next generation technologies and products that are currently in the spotlight include optoelectronics based on organic materials. For instance, typical optoelectronic devices include organic light-emitting diodes (OLEDs) which are used in mobile displays or for solid-state lighting (SSL) as well as organic photovoltaic cells in which a light-absorbing layer is formed from an organic material. As the results of studies focused on organic materials for optoelectronic devices, organic materials having considerable performance are being developed.
Such an optoelectronic device includes an organic/inorganic composite layer in which organic and inorganic materials are combined. Typical examples of inorganic materials used in the optoelectronic device include a transparent electrode, a reflective metal electrode, a glass substrate and the like. However, since a significant amount of optical loss occurs in inorganic materials due to different refractive indices, an improvement in optical efficiency is significantly limited.
In order to overcome this problem, in the related art, a nano-pattern having a patterned structure is formed in the front part of the optoelectronic device. However, when the nano-pattern is formed on the organic/inorganic composite layer of the optoelectronic device, it is impossible to ensure that thin films of the organic/inorganic composite layer be flat since the nano-pattern forms an uneven surface. When the nano-pattern is formed on the organic/inorganic composite layer, there is a high possibility that a localized sharp portion be formed on the organic/inorganic composite layer that is bonded to the nano-pattern. For instance, since an OLED has a multilayer structure consisting of very thin organic/inorganic films, the sharp protruding portion may be transferred from the nano-pattern to the anode that is bonded to the nano-pattern. Then, a current will be concentrated in that sharp protruding portion of the anode, which is a cause of a large leakage current or decreases power efficiency.
Therefore, in order to prevent such deterioration of electric characteristics, a planarization film is necessarily added.
However, perfectly planarizing the patterned nano-pattern using a thin planarization film having a thickness of several hundreds of nanometers is extremely difficult in an actual process. That is, in the related art in which a planarization film is deposited on the nano-pattern, since a material that forms the planarization film is deposited following the nano-pattern, the planarization film resembles the geometry of the nano-pattern and thus the flatness of the planarization film is very low.
The information disclosed in the Background of the Invention section is provided only for better understanding of the background of the invention and should not be taken as an acknowledgment or any form of suggestion that this information forms a prior art that would already be known to a person skilled in the art.